Improved chord for bridges



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C. SHALER SMITH, OF BALTIMORE, MARYLAND, ASSIGNOR 'TO SMITH, LAVTROBE, AND COMPANY, OF SAME PLACE.

Leners Patent No.' 93,917, dated August 17,1869.

IMPRovED cHoRD PoR BRIDGES.

The Schedulev referred to in these Lettera Patent and making part of thel same.

` ments in the Construction of Chords for Bridges; and

I hereby declare the following to be a full, clear, and exact description of the same. reference being had to 4the accompanying drawings.

The chord in which my inventien consists, while intended more especially to meet the requirements of deck-bridges, so called. is nevertheless adapted for usevwith any suitable system of bridge.

The object I have in view is to combine, in one chord, the excellent qualities of the cylinder to resist compression, and the similarlygood qualities ofthe I-beam to resist transverse strain from the crossties or otherA superstructure. To this end,

My invention consists of a chord composed of a sectional tubularv column of cast or wrought-iron,

combined with an I-beam extending longitudinally through the column, and dividing itinto two parts, which are secured to said beam as hereinafter described.

In illustration of my invention, I have represented, in

Figure 1,what is known las a four-segment Phoenix column, .combined with the I-beam, which extends the length of the column and through its axis.

Figure 2' is a transverse section of the' same. The cylinder is divided by the beam-web into two equal parts, applied to each side of the beam, between its upper and lower anges, and held in place by rivets extending through thc iianges of the column and the intermediate beam.

Figures 3 and 4 represent a method of combining twobeams when the column is of too great ,diameter to admit of one beam passing through it.

The column is an eight-segment Phnix column,

land as its diameter .is too great for one beam, two

are united, by setting the lower ijange of the upper beam on the upperflange of the lower, the two flanges being then united by rivets, bolts, .or other suitable means. Y

' The construction of the chord does not vary in other respects from that shown in iig. l.

'These examples are suicient to indicate the nature and value of my invention, and the manner in which the'beam can be combined with a column of any diameter.

The form of the column itself is admirably adapted to resist compression, while the capacity ofthe Ill-beam to resist transverse strain from the cross-ties of the deck-bridge or other superstructure is well known.

By thus combining these two qualifications, I pro- -duce a sandwiched chord, which is in every way better fitted for use than other chords heretofore employed for like purposes.

The use of the beam 1n this connection enables me to make the chord of -less sectional area than would otherwise be requiredin order to resist the strain, the web of beam around the neutral axis ofthe chord being utilized, in order to bring the chord to the required standard.

Assuming that thirty inches of section is required for compressive strain, and ten inches for the transverse strain therejvould be,'theoretically, forty inches section required; butas the only practicableiorm of fbeam of sutiicient depth to resist the transverse strain contains in itself twenty inches section, the chord, as ordinarily built, wouldV contain fifty inches, while, by my improvement, I am lenabled to'olace a compressive strain upon the surplus ten inches around the neutral axis of the beam, andl thereby reduce the section 'of the cylindrical portion of the chord to twenty inches, thus using only the forty inches total section'theoretically required.

I have represented, for the purpose. of illustrating my invention, the I-beam, applied to a Phoenix co1- umn, but I do not wish to be understood as limiting myself to this special application. Any other form of column, whether of wrought or cast-iron, or steel, ma)Y be employed in lieu ot' the one represented, -to which the beam can be applied in the manner hereinbefore specified. v

Haring now described my invention, and the manner in which the same is or may be carried into effect,

\Vliat I claim, and desire to secure by Letters Pat ent, is-

A chord, for deck and other bridges, composed of a sectional tubular column divided longitudinally by an I-beam, or a beam composed of two or more :x2-beams united, with which the sections of said tubular column are combined, substantially as and for the purposes set forth.

In testimony" whereof, I have signed my name to this specification, before two subscribing witnesses.

. SHALER SMITH.

lVitnesses JOHN A. KAY, RoBT. P. ELWoR'rnY. 

